This book, Active Filters and Amplifier Frequency Response, is the third of four books of a larger work, Fundamentals of Electronics. It is comprised of three chapters that describe the frequency dependent response of electronic circuits. This book begins with an extensive tutorial on creating and using Bode Diagrams that leads to the modeling and design of active filters using operational amplifiers. The second chapter starts by focusing on bypass and coupling capacitors and, after introducing high-frequency modeling of bipolar and field-effect transistors, extensively develops the high- and low-frequency response of a variety of common electronic amplifiers. The final chapter expands the frequency-dependent discussion to feedback amplifiers, the possibility of instabilities, and remedies for good amplifier design. Fundamentals of Electronics has been designed primarily for use in an upper division course in electronics for electrical engineering students and for working professionals. Typically such a course spans a full academic year consisting of two semesters or three quarters. As such, Active Filters and Amplifier Frequency Response, and the first two books in the series, Electronic Devices and Circuit Applications, and Amplifiers: Analysis and Design, form an appropriate body of material for such a course.